california abalone aquaculture

8/12/2019 California Abalone Aquaculture

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University of California, Davis Department of Animal Science

1ASAQ-A10 6-96

The Abalone Fishery

Abalone, marine snails of the genusHaliotis,

have occupied the rocky intertidal and subtidal

areas of the Pacific coast from Alaska to Baja

California for at least 100 million years. Since

human occupation of North America these

mollusks have been important to the lifestyle

and economy of all Pacific coast populations.Native Americans valued the abalone, using

the meat as a source of food and the shell for

implements, trade material and decoration.

Each successive human culture immigrating to

the Pacific coast has recognized the value of

abalone. Pacific coast commercial fishing for

the eight species of abalone began in the mid-

nineteenth century (Table 1). By the mid-

twentieth century abalone populations had

come under intensive fishing pressure as

coastal population grew and fishing technology

improved. Commercial fishing peaked at an

annual harvest of over 2500 tons in 1957.

About 2000 tons were harvested annually from

1957 to 1969, followed by a serious and con-

tinuing decline in commercial landings and

abalone abundance since 1969. Commercialabalone landings for 1992, 1993 and 1994 were

approximately 260, 230 and 140 tons, respec-

tively. The red, pink and green abalone com-

prise most of the commercial take, but all Cali-

fornia abalone species are in serious decline.

Both commercial and sports fishing are regu-

lated by specific size limits for each species of

abalone, and a bag limit for each category of

harvest. The black abalone fishery was closed

in 1993 because of mortalities caused by With-

ering Syndrome, a disease that affects theabalone's foot. The disease has reduced black

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CALIFORNIA ABALONE AQUACULTURE

CONTENTS

The Abalone Fishery ............... ............... 1Abalone Aquaculture ............................. 2

The Abalone Hatchery....... ................. ... 2Eggs and Larvae .......................................... 2

Juvenile Abalone.......................................... 3Natural Diets ............................................... 3Artificial Diets.............................................. 3

Intermediate or Weaning Systems...... 3Growout or Production Systems......... 4

Cage Culture Systems................................ 4Land Based Systems ................................... 4Source of Kelp ............................................. 4

Production & Marketing ....................... 5Production.................................................... 5Marketing ..................................................... 5

Table 1. Abalone (GenusHaliotis) found in

California coastal waters.

Common Name Species Name

Red abalone H. rufescens

Pink abalone H. corrugata

Green abalone H. fulgens

Black abalone H. cracherodii

White abalone H. sorenseni

Threaded abalone H. assimilis*

Pinto abalone H. kamtschatkana

Flat abalone H. walallensis

* Considered by some to be a subspecies of the Pinto

abalone. Several hybrid crosses of abalone have been

reported from California waters.


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abalone populations near the Channel Islands

to 10 percent of their 1986 levels. The decline

in abalone abundance in California parallels

the decline of abalone populations internation-

ally. Overfishing has impacted the world

abalone catch among the major fisheries, in-

cluding that of Japan, Mexico, Australia,

South Africa, and Korea. These declines,

coupled with the value of abalone meat on the

world market, have promoted the concept of

abalone aquaculture internationally, both to

supplement the world supply of abalone meat

and as an enhancement tool to mitigate the

damage to the fishery.

Abalone AquacultureAbalone culture in California was first attempt-

ed at Stanford's Hopkins Marine Station at

Pacific Grove in 1940. Initial efforts focused

on spawning adult red abalone and studying the

larval stages. California's commercial abalone

industry began as industry research and devel-

opment (R&D) near Morro Bay in 1964. For

over 20 years commercial R&D efforts contin-

ued, with additional research being conducted

by the California Department of Fish and

Game and the University of California. By the

late 1980s the first commercial abalone farms

were in transition from R&D to commercial

viability, and currently there are about ten

commercial operations in California.

Abalone growers have cultured nearly all of the

California species. However, because of their

value and adaptation to culture technology, the

red abalone and, to a lesser extent, the pink and

green abaloneare the principal species grown

in California aquaculture facilities. The pinkand the green abalone are of greatest interest to

growers in southern California because they

can be grown at relatively higher water temper-

atures.

The Abalone Hatchery

Eggs and Larvae: Adult male and female

abalone are maintained as broodstock, and then

induced to spawn using either ultraviolet irradi-ated seawater or a solution of hydrogen perox-

ide. Both methods stimulate mature female

abalone to release unfertilized eggs (called

ova) and males to release sperm. An 8 inch

mature female abalone may release in excess of

11 million ova of which 6 to 8 million will be

fertilized and become viable eggs. Each ova is

about 200 (1.0 = one micron = 0.001 mm =

0.000039 inch). The ova are mixed with a

concentration of sperm and seawater, and the

fertilized eggs begin cell division within twohours.

During the hatchery phase, the fertilized eggs

are hatched and reared through the trochophore

and veliger, free-swimming larval stages. The

larvae are contained in flow-through water

systems equipped with screens to prevent their

escape. To protect the young abalone

hatcheries use filtered and UV-treated water

for all sensitive, early life stages. During this

period the developing eggs and larvae derive

nutrition primarily from yolk reserves. Some

nutrient material is obtained from dissolved

organic materials in the seawater. Eggs and

larvae are reared in seawater at a temperature

of about 15C (59F). The rate of development

is temperature-dependent. Warmer water tem-

peratures increase the rate of larval develop-

ment, but increase the risk of bacterial infec-

tion in the culture systems.

At 15C the eggs hatch and release ciliated,

free swimming trochophore larvae within 16 to20 hours. Within 26 to 30 hours after fertiliza-

tion, the trochophore larva secretes a protective

larval shell and transforms into the veliger

stage. The veliger is characterized by a re-

tractable velum, a ciliated leaf-like organ used



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for locomotion and respiration. As the veliger

continues to develop, it forms an apical cone,

undergoes a "typical" gastropod torsion

(twisting of the body), the larval foot begins to

form, eyespots develop, and the tentacle buds

can be seen. Hatchery operators use these ob-

servations to judge the development and health

of the larvae. When the veliger larva begins to

"test" the substrate with its larval foot, the

hatchery operator knows that it is ready to

leave the water column and begin the crawling

phase of its life cycle. Once settled, the veliger

sheds its cilia and develops the juvenile shell

and body form and characteristic abalone foot.

Juvenile Abalone: The first two months fol-lowing settlement are the most critical to sur-

vival of juvenile abalone in culture systems.

Juvenile abalone are reared in flow-through

tank systems, and control of the environmental

conditions such as temperature, water quality,

and feed are essential. In general, water tem-

perature is species-dependent, but usually

range between 15 to 18 C. Water quality is

determined by initial site selection in an area

with an oceanic influence and water of 30 to 35

ppt (parts per thousand or g/liter) salinity. Itshould be free from harmful contaminants and

monitored for temperature, pH, oxygen, and

ammonia, and only filtered and UV-treated

water used during these early life stages.

Natural Diets:Because all postlarval abalone

are grazers, the animals are fed benthic (bottom

growing) microalgae that is cultured at the

facilities and seeded into the tank prior to in-

troduction of the abalone. These diatoms form

a thin surface film in the tank that is grazed bythe young abalone. Maintaining a continuous

supply of these diatoms in volumes sufficient

to feed commercial densities of abalone is

critical to a successful commercial operation.

The abalone aquaculture industry has tradition-

ally fed microalgal (benthic diatoms) diets to

young juvenile abalone. Research suggests

that the abalone also derives nutrition from

bacteria, yeast and other microorganisms asso-

ciated with the diatoms. Commercial opera-

tions producing million to 1 million seed

abalone per year sometimes have difficulty

sustaining a healthy diatom growth in the cul-

ture tanks.

Artificial diets:Because of the uncertainty

that always exists when feeding living diets to

aquaculture animals, there is great interest in

recent research in abalone nutrition and devel-

opment of artificial abalone diets. The essen-

tial ingredients for an abalone diet are fairly

well established. Developmental diets containabout 30 to 50 percent protein, 30 to 40 percent

carbohydrate, and about 5 to 6 percent each of

fat, fiber, and ash. The protein source can be

fish meal or milk by-products, and the carbo-

hydrate is usually from seaweed. Sometimes

minerals and vitamin supplements are added.

Research is also being conducted to determine

the value of the combination of benthic algae

and artificial diet as feed for young abalone.

All abalone-producing countries have one or

more university research groups or commercial

businesses involved in the development of

abalone diets. Many California producers have

found the artificial diets particularly useful for

abalone between 3 and 6 months of age.

Abalone Intermediate or Weaning

Systems

When juvenile abalone are about 4 to 6 months

of age and about 6.4 to 13.0 mm ( to inch)

in shell length they are called "seed abalone".

The seed abalone are transferred from thehatchery to intermediate culture systems, usu-

ally consisting of tanks with floating plastic

mesh baskets containing fiberglass or PVC

structures on which the abalone crawl.



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This stage of culture is sometimes called

"weaning" since the abalone are weaned from

their earlier diets to a diet of the giant kelp,

Macrocystis pyrifera,or other large brown kelp

such asNereocystus luetkeana. Kelp is a natu-

ral food of the species of California abalone,

and at this size the abalone's mouth parts are

sufficiently developed to graze on the thicker,

tougher fronds of the kelp. The abalone are

held at high densities, and kelp is literally

stuffed into the baskets around the internal

structures, thereby providing the abalone with

easy access to the new food. From this point

forward, the abalone are maintained on a diet

of kelp. The seed abalone are held in the inter-mediate system for 2 to 6 months or until they

reach about 15.0 to 25.0 mm ( to 1.0 inch) in

shell length. At this point they may be sold as

seed abalone to another company or transferred

to a growout system within the parent com-

pany.

Abalone Growout or Production

Systems

California growout systems have evolved from

modifications of a number of designs pio-neered by early California growers and other

abalone growers internationally. Growout

systems have included near-shore submerged

and screened concrete pipe culverts, fifty-five

gallon plastic barrels, and off-shore cage cul-

ture. Contemporary growers primarily use

cage culture and land-based, flow-through tank

systems.

Cage culture system: The cage culture sys-

tem evolved from early barrel culture methods.

Rectangular cages have proven more efficient,easier to handle, and give better survival rates

than barrels. The cage culture system is used

by several commercial operations in California

and in Mexico's Baja California.

Many abalone cages are built by abalone grow-

ers, but commercially constructed cages

(SeaCage) are available. Cages are often

constructed from PVC frames covered with

heavy gage plastic mesh. Additional surface

area is provided to the abalone by securing

plastic or fiberglass plates in the cages. The

cages are suspended from longline systems or

from floating docks that provide access. Addi-

tional economic considerations should include

costs for boat, motor, fuel, access time, and

hydraulic wench to lift the cages for feeding,

maintenance, and harvest.

Land-based, flow-through tank systems:

Land-based growout production systems usu-

ally consist of reinforced concrete or fiberglass

tanks of 1000 to 2000 gallon capacity that areplumbed for flow-through seawater and forced

air. They should include secondary back-up

systems for pumped seawater and forced air to

provide the necessary oxygenated water essen-

tial to abalone survival. Energy expenditures

to operate the seawater pumping and aeration

systems are a major cost for land-based sys-

tems.

In both cages and flow-through tanks, it takes 3

to 4 years for abalone to grow to a commercial

marketing size of about 7.6 to 8.9 cm (3 to 3

inches). This is the most capital intensive and

time-consuming portion of abalone aquacul-

ture, and labor and feed costs are a major con-

sideration for both types of culture systems.

Source of kelp: Kelp for abalone intermediate

and growout production is harvested from

California's offshore kelp beds, and regulated

under permits issued by the California Depart-

ment of Fish and Game (CDFG). An abalone

farm has the option to harvest kelp using itsown vessel and operators or to purchase kelp

from a licensed kelp-harvesting company.

Kelp is harvested for use in a number of prod-

ucts ranging from ingredients used to culture

bacteria to stabilizers for ice cream. About



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half of the kelp beds in California off-shore

waters are designated as "open" by the

CDFG, and anyone with a permit can harvest

kelp from these beds. Several abalone farmslease specific kelp beds from the State and

have exclusive harvesting rights on these

beds. The harvest of kelp is highly regulated

and monitored by the Fish and Game Com-

mission. Whether harvested from open or

leased beds, kelp can only be cut at a depth of

four feet below the surface. Regulations are

designed to maintain a sustainable resource.

Commercial growers also collect, dry and

store kelp to prepare for feeding during times

when seas are too rough to collect fresh kelp.Abalone Production and Marketing

Production: Estimated California abalone

aquaculture production for 1992 was 132,000

pounds of live abalone valued at $2 million.

In 1994 estimated production was 242,000

pounds valued at about $3.1 million.

Marketing: Abalone products are marketed

as an up-scale product. Its high international

market value allows growers to recoup an

expensive and relatively long-term produc-tion investment. In general, the demand for

abalone exceeds the supply. For example, in

1993 Japanese harvest of their native abalone

was approximately 2,000 tons, but Japanese

demand for abalone product was about 4,000

metric tons. The Japanese import abalone

from China, Korea, Australia and California.

Most California abalone aquaculture opera-

tions include a marketing partner for product

development. Abalone are primarily mar-

keted live to domestic and international mar-

kets, and shipment of live abalone is

presently considered the most cost effective

and desirable market for growers. In 1994,

60 percent of cultured abalone were sold live,30 percent were sold as shucked meat, and 10

percent were sold in other forms including as

seed. Major international markets are Japan,

Taiwan and Hong Kong. Domestic markets

include white tablecloth restaurants, seafood

markets, sushi bars, and resorts throughout

the continental United States

References and Suggested ReadingConte, F.S. 1981. Abalone aquaculture. California

Aquaculture Newsletter (81-2). 3 pp.

Conte, F.S. 1993.Abalone aquaculture. AnimalScience Aquaculture Flier, ASAQ-A10-1/88-5/93. 4

pp.

Ebert, E.E. 1992.Abalone. In: California's living

marine resources and their utilization. Leet, Dewees,

and Haugen (Editors). Sea Grant Extension Publica-tion UCSGEP-92-12. 257 pp.

Haaker, P.L., K.C. Henderson, and D.O. Parker.

1986. California abalone. CDFG Marine ResourcesLeaflet No.11. 16 pp.

Hahn, Kirk D. (Editor). 1988.CRC handbook of

culture of abalone and other marine gastropods. CRCPress, Inc., Boca Raton, FL 348 pp.

La Touche, B., K. Moylan, and W. Twomey. 1993.

Abalone on-growing manual. BIM Aquaculture Tech-nical Section, Dun Laoghaire, Co. Dublin. 39 pp.

Leighton, D.L. 1989. Abalone (GenusHaliotis)

mariculture on the North American Pacific Coast.Fisheries Bulletin 87(3): 689-702.

The University of California Cooperative Extension in compliance with the Civil Rights Act of 1964, Title IX of the Education Amendments of 1972, andthe Rehabilitation Act of 1973 does not discriminate on the basis of race, creed, religion, color, national origin, sex, or mental or physical handicap in any

of its programs or activities. Inquiries regarding this policy may be directed to: Affirmative Action Officer, 317 University Hall, University of California,Berkeley, California 94720, (510) 642-0903.

University of California and the United States Department of Agriculture cooperating.

Fred S. Conte

Department of Animal Science

University of California, Davis

Susan McBride

University of California,

Sea Grant Extension Program

california abalone aquaculture

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